1. Field of the Invention
The present invention relates to information processing apparatuses and methods, information recording medium manufacturing apparatuses and methods, and information recording media. More particularly, the invention relates to an information processing apparatus and method, an information recording medium manufacturing apparatus and method, and an information recording medium that allow the execution of security check processing by using content codes recorded, as a content usage control program, on the information recording medium together with content.
2. Description of the Related Art
Various software data (hereinafter referred to as “content”), such as audio data, e.g., music, image data, e.g., movies, game programs, and various application programs, can be stored on recording media, for example, Blu-ray discs (trademark) using blue laser light, digital versatile discs (DVDs), mini discs (MDs), compact discs (CDs), as digital data. In particular, Blu-ray discs (trademark) using blue laser light are high-density recording discs and can record a large volume of video content as high-quality image data.
Digital content is stored in various information recording media, such as those described above, and is provided to users. A user uses the digital content by playing it back on the user's personal computer (PC) or a player, such as a disc player.
Generally, the distribution rights of many content data, such as music data and image data, are owned by creators or sellers of such content data. Basically, therefore, certain usage restrictions are imposed when distributing content, that is, the use of content is allowed only for authorized users, thereby preventing unauthorized copying.
According to digital recording apparatuses and recording media, images and sound can be repeatedly recorded and played back without a loss in quality. Thus, the distribution of illegally copied content via the Internet, the circulation of recording media, such as compact disc recordable (CD-R) discs, recording copied content thereon, so-called “pirated discs”, and the use of copied content stored in hard disks of, for example, PCs, are widespread.
DVDs or large-capacity recording media, such as those using blue laser light which have recently been developed, can record a large volume of data, for example, up to several movies, on one medium, as digital information. Since video information can be recorded as digital information as described above, it is becoming important to perform copyright protection by preventing unauthorized copying. Nowadays, to prevent unauthorized copying of digital data, various techniques for preventing unauthorized copying are practically applied to digital recording apparatuses or recording media.
One of the measures to enhance copyright protection is to encrypt content. According to this measure, however, if leakage of cryptographic keys used for encrypting content occurs, it is difficult to prevent unauthorized copying of content and distribution of such copied content. One measure to solve such a problem is the configuration disclosed in Japanese Unexamined Patent Application Publication No. 2002-311998. In this configuration, content is recorded in the state in which part of content data is substituted by dummy data so that unauthorized playback of the content can be prevented.
When playing back content including dummy data, it is necessary to replace the dummy data by correct content data. This data conversion processing should be performed while preventing leakage of the correct content data, and certain measures are also preferably taken to prevent leakage of processing information, such as the location of dummy data and the conversion method.
As discussed above, when playing back content, it is necessary to execute content decryption processing and data conversion processing, and in some cases, security check, such as integrity checking processing to determine whether an information processing apparatus or a playback (player) program that is to use content is an authorized apparatus or program having a license, is conducted. Such data processing is performed by executing content codes recorded, as a content usage control program, on an information recording medium together with content. An example of content usage processing using content codes is disclosed in, for example, WO2005/008385.
Content codes are set as a file independent of content and are recorded on an information recording medium. Accordingly, it is possible that only content codes be moved or copied onto another information recording medium. If leakage of content codes occurs, which may lead to unauthorized distribution and usage of the content, it is likely that many items of content are illegally played back and used, causing enormous damage.
It can be assumed that various types of apparatuses or applications manufactured by different manufacturers be used for playing back content. If security check using content codes is performed according to only one common sequence, it is difficult to perform sufficient checking depending on the types of apparatuses or application. Additionally, a file for performing security check for each playback apparatus is probably used regardless of type of content, and thus, it is desirable that the file be reused.